combine fiberglass batt & ridged insulat
nash
| Posted in Energy, Heating & Insulation on
hello,
just wanted some opinions on a insulation question. I’m looking to insulate my attic space and finish it. I have 2×8 rafters 16 oc. it seems batt insulation is available for
2×6 walls and 2×10 walls, I have not seen it for 2×8’s yet. I was wondering if it make sense to put a combination of the 2×6 batt and a 3/4 or 1 inch ridgid insulation to gain the max r-value vs. cost. spray foam is not really an option. I will maintain a 1 inch gap with roof sheathing. What method of installation can you suggest. fiberglass or ridgid first ? what type of ridgid insul should I use.
The house is approx 100 years old and in new york city area.
Any help would be greatly appreciated
thanks
Replies
You can get FG batts for 2x8 depth if you want.
I will maintain a 1 inch gap with roof sheathing
Is the roof vented with ridge vent & soffit vents now?
Joe G
just had roof re-done and yes ridge and soffit vents were put in
You have to be aware of vapor transmission,or not transmitting due to vapor barriers or the type of foam, through the foam as you dont want condensation on the warm side. Go to Building Science.com for more info.